What does an identity matrix do? Precalculus Matrix Algebra Identity Matrix 1 Answer Daniel L. May 23, 2015 In fact it does nothing. The identity matrix is such a matrix #I#, for which #AA_A I*A=A*I=A#. This definition means, that the identity matrix is such a matrix, which doesn't change another matrix, when multiplied Answer link Related questions What is an identity matrix? How do I find the additive identity matrix? What is the identity matrix for subtraction? What is the identity matrix of size 4? What is the identity matrix of a #2xx2# matrix? What is the identity matrix of a #3xx3# matrix? How do I find the identity of a matrix on a graphing calculator? What is a unit matrix? How to determine whether a matrices are in echelon form, reduced echelon form or not in echelon form ? Question #f6f93 See all questions in Identity Matrix Impact of this question 2379 views around the world You can reuse this answer Creative Commons License